Walking beam furnace



' .Oct. 7, 1969 c. CONE 3,471,134

I WALKING BEAM FURNACE Filed Feb. 26. 1968 k 7 Sheets-Sheet 1 8 INVENTOR.

Carma (0N5 A-r-ra/zmsr Oct. 7, 1969 c. CONE 3,471,134

WALKING BEAM FURNACE v I Filed Feb. 26, 1968 7 Sheets-Sheet 2 1 ,IIIII'II'IIIIII "IIII/IIIIIIIIII II-III" (menu (9N6 1 Y INVENTOR.

Oct. 7, 1969 c. cows WALKING BEAM FURNACE Filed Feb. 26, 1968 '7 Sheets-Sheet 3 ATTORNEY Oct. 7, 1969 c, CONE WALKING BEAM FURNACE 7 Sheets-Sheet 1 Filed Feb. 26, 1968 Arron/J67 Oct. 7, 1969 c. CONE v 3,471,134

WALKING BEAM FURNACE Fil ed Feb. 26, 1968 7 Sheets-Sheet 5 INVENTQR, 692:0 w:

Arro nos? Ill Oct. 7, 1969 c, C'ONE v WALKING BEAM FURNACE 7 sheet s Sheet e Filed Feb. 26, 1968 I IN\ 'ENTOR. (HREOZL 61w:

A-r-roeusr Oct. 7, 1969 c. CONE WALKING BEAM FURNACE 7 Sheets-Sheet 7 Filed Feb. 26, 1968 INVENTOR. I (42204; (a/v5 BY z.

Arrozu'f United States Patent O 3,471,134 WALKING BEAM FURNACE Carroll Cone, Maumee, Ohio, assignor to Midland-Ross Corporation, Toledo, Ohio, a corporation of Ohio Filed Feb. 26, 1968, Ser. No. 708,045 Int. Cl. F27b 9/24; B65g 25/04 US. Cl. 263-6 16 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a furnace with a conveyor of the walking beam type having a fixed set of parallel'horizontally disposed rails and a reciprocable carriage with a set of similarly disposed rails for intermittently and alternatively holding and conveying a series of slabs, blooms, or billets during their passage through the furnace. The carriage is supported upon roller-ringed eccentrics so it may be moved vertically and horizontally and the movement in one direction is substantially independent of the movement in the other direction. Rows of vertical columns which extend through aligned slots in the floor of the furnace are attached to the carriage and are sealed to the floor of the furnace by a fluid trough means mounted on the carriage and having scrapers for removing loose scale which falls from the workpieces through the slots and into the seal trough means. The vertical columns and the horizontal rails mounted thereon are internally cooled by a circulating fluid and exterio rly insulated. A multiplicity of solid cylindrical workpiece support pads are butt welded to the top of the rails'in a spaced relationship with respect to each other, so that the surface area of a workpiece in contact with any one of the support pads during a subsequent cycle of the conveyor is not the same surface as was in contact with any one of the support pads during the immediately preceding cycle.

BACKGROUND OF INVENTION Tunnel type furnaces with conveyor mechanisms having reciprocable conveyor members for simultaneously advancing a plurality of workpieces through the furnace in a series of steps are well known and sometimes commonly referred to as walking beam furnaces. Examples of such furnaces are described and shown in United States Patents 2,235,771 (G. R. McDermott) issued Mar. 18, 1941 and 2,858,122 (C. MacGregor) issued Oct. 28, 1958.

Walking beam conveyors were developed for furnaces used in heating steel billets, slabs, and large round stock to overcome the problems encountered with pusher type furnaces where the work pieces were butted together and pushed through the furnace on stationary rails by a ram located at the entrance end of the furnace. Frictional engagement with the rails generally resulted in a surface blemish on the heated workpiece that was impossible or difficult to remove in the subsequent forming or rolling operations. Also, when portions of the workpieces remained in constant contact with the rails, these portions were chilled or not heated properly, particularly if the rails were made of a metal which had to be cooled, such as by an internal flow of water. To equalize the temperature throughout the workpiece and thus remove the chilled spots, the workpiece had to be pushed over a soaking hearth on a refractory surface where it was subjected to intense heat for a period of time.

Some other problems common to pusher type tunnel furnaces were that they were not self emptying and various sizes and thicknesses of stock could not be randomly scheduled through the furnace. A series of thin slabs would tend to buckle if pushed through behind one or more heavy slabs.

3,471,134 Patented Oct. 7, 1969 ICC Prior art walking beam furnaces overcame these problems to some degree, but many of their conveyors were complicated, unreliable, costly to build and maintain and difficult to operate, especially when the gross weight of the reciprocable conveyor and a full load of workpieces approached 1,500,000-2,000,000 pounds in weight. Walking"- beam conveyors, in which the vertical and horizontal travel were not independent of each other, encountered tracking problems when warped billets or slabs were being conveyed through the furnace. On such conveyors one side of a badly warped workpiece could be lifted free from the stationary rails and simultaneously begin its horizontal travel while the other side was still in firm contact with its stationary rails and therefore not being carried forward during the first portion of the walking beam cycle.

Surface blemishes and chilled spots still remained a problem in prior art furnaces having walking beam conveyors even though the heated and partially softened workpiece was not skidded along on the top of conveyor rails or in constant contact with any one set of rails.

Another problem encountered, particularly with walking beam conveyors which had reciprocable vertical columns extending through elongated slots in the floor of the furnace, was the effective sealing of these slots. The uncontrolled entry of air through these slots had a cooling effect and it interfered with the operating atmospheric pressures in the heating chamber of the furnace. Various sliding plate types of mechanical seals have been developed, but due to the heat within the furnace and the usual accumulation of scale which flakes off from the metal workpieces during heating, the workability of the seal or the reciprocation of the conveyor was impaired.

OBJECTS AND ADVANTAGES It is an object of this invention to produce a furnace apparatus for heating and conveying a plurality of large steel slabs, blooms, or billets at one time and by which each of such workpieces may be readily heated to a uniform temperature throughout.

It is another object of this invention to produce a walking beam furnace which will effectively convey elongated workpieces laterally through the furnace even though the workpieces are warped.

It is still another object of this invention to produce such a furnace with a conveyor member which may be reciprocated in a vertical direction and in a horizontal direction either separately or simultaneously.

It is yet another object of this invention to produce .a reciprocable conveyor for a slab furnace which permits effective exposure of all of the surface area of the slab to the heat within the furnace.

It is a further object of this invention to produce a walking beam conveyor rail which has support pads that practically obviate or reduce surface blemishes and chilled spots in a heated slab normally caused by contact with the slab supports.

It is a still further object of this invention to produce a reciprocable conveyor for a furnace in which reciprocable members extend through slots in the floor of the furnace and in which these slots are hermetrically sealed by a fluid trough means.

It is still another object of this invention to produce a walking beam type conveyor which will efficiently handle gross loads in excess of 1,500,000 pounds and which is of simple rugged construction that is easy to operate and maintain.

The above mentioned and other objects and advantages and the manner of attaining them are described below by reference to the embodiment of this invention shown in accompanying drawings.

3 A BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional side elevational view with parts broken away, showing the furnace hearth and the conveying structure with the reciprocable portion of the conveyor at the lowest position of its lift cycle and at the starting position of its horizontal travel cycle.

FIG. 2 is a sectional plan view of FIG. 1 taken along line 2-2 of FIG. 1.

FIG. 3 is an enlarged sectional end view of FIG. 1 taken along line 3-3.

FIG. 4 is an enlarged plan view of the horizontal travel drive, the vertical lift drive and the reciprocable carriage with parts broken away.

FIG. 5 is an elevational view taken along line 55 of FIG. 4, but including more details of the reciprocable carriage.

FIG. 6 is an enlarged sectional view of the eccentric lift taken along lines 66 of FIG. 5 showing details of its peripheral roller ring.

FIG. 7 is an enlarged longitudinal sectional view of the entrance end of the furnace and conveyor of FIG. 1 showing details of the liquid seal trough including its sediment and scale removal mechanism and one of the liquid seals for the vertical columns of the reciprocable conveyor.

FIG. 8 is an enlarged side view of a section of the conveyor showing one of the workpiece support nodules butt welded to the horizontal rail of the conveyor and also showing how a portion of the liquid coolant is diverted from the tubular horizontal rail into one of the vertical columns.

FIG. 9 is a sectional view of FIG. 8 taken along line 99.

DETAILED DESCRIPTION OF THE INVENTION FIGS. 1, 2 and 3 show a conveyorized furnace having an elongated refractory chamber 22 with a roof 24, floor 26, side walls 28 and 30, and end walls 32 and 34. These end walls 32 and 34 define an entry end opening 36 and an extractor end opening 38 which have closures or sliding doors 40 and 42 respectively. Structural beam members form a cage around the refractory chamber and provide reinforcement and support for its members. The lateral floor supporting beams 44 are mounted upon four equally spaced rows 45, 46, 47, and 48 of underpinning or bridgework with the outside rows 45 and 48 being located substantially beneath side walls 28 and 30 respectively. The bn'dgework is of suflicient height to provide space beneath the bottom of the floor beams 44 for easy access to the underlying parts and assemblies associated with the reciprocable conveyor member.

The refractory chamber 22 has cross-firing upper 50 and lower 52 banks of burners located along its side walls 28 and 30. The burners in the upper banls 50 of each wall are horizontally aligned, but are vertically offset with respect to the horizontally aligned burners of its lower bank 52. The side walls 28 and 30 may also contain a plurality of flue openings spaced inwardly from the ends 32 and 34 of the refractory chamber 22 and extending from the floor 26 to the roof 24. The flue openings in one wall 28 may be offset longitudinally from the flue openings in the opposite wall 30. Preferably separate heat recuperating flue means 54 are attached to each of these flue openings. Adjustable dampers 56 are provided in each of the flue means 54 for regulating the flow of combustion products out of the furnace 20 and also for regulating the atmospheric pressure within the refractory chamber 22.

The walking beam type conveyor comprises a fixed conveyor assembly 58 and a movable conveyor assembly 60. The fixed conveyor assembly 58 lies substantially within the refractory chamber 22 and has a plurality of vertically disposed tubular columns 62 arranged in rows extending longitudinally and laterally of the refractory chamber 22. The columns 62 are arranged in lateral rows so that the burners of the lower bank 52 may be severally placed centrally between the rows and be directed to fire parallel with these rows. Thus the columns 62 do not tend to interrupt the flames emanating from the burners or to shield the workpieces from the flames. These columns 62 are rigidly mounted on the supporting framework for the floor 26 and they extend upwardly about one-half the height of the chamber 22. At the top of each longitudinal row of columns 62, a horizontally disposed tubular rail 64 is attached so as to be in fluid communication with each of the upright columns 62 (see FIG. 8). Six of such rails 64 are shown in FIGS. 2 and 3, but more or fewer rails may be used Without departing from the scope of this invention. The columns 62 and rails 64 have the same cross-sectional dimension. The end of each rail 64, adjacent the outlet opening 38 of the refractory chamber 22, extends beyond the last upright column 62' into the outlet opening 38 and then has a recurved or goose-necked section 66 which is joined in end to end relationship with the top of shortened vertical column 62 (see FIG. 1).

A cooling fluid, such as water, may be introduced at the bottom end of each tubular column 62 and caused to flow through the rails 64 towards the entry end 32 of the refractory chamber 22 and then out of the bottom of the upright columns 62" connected to the other ends of rails 64. The upright columns 62 intermediate the end columns 62 and 62" may contain diverter tubes 68 for circulating a portion of the cooling fluid flowing through the rails 64 into the vertical columns 62 (see FIGS. 8 and 9). The external diameter of the diverter tubes 68 is substantially less than the interinal diameter of the columns 62 and rails 64. Each diverter tube 68 has a short elbow section 70 with its open end extending into the tubular rail 64 and facing in an upstream direction. The other end of elbow 70 is integrally connected to a leg section 72 which extends downwardly through the center of the column 62 and terminates a short distance above the base of this column. Thus a portion of the cooling fluid flowing through each rail 64 is diverted downwardly through the diverter tubes 68 into the base portion of the columns 62 and from there upwardly between the diverter tubes 68 and columns 62 whereupon it is returned to the main stream in the rail 64. Since sediment may build up in the bottom of the vertical columns 62 and eventually clog the lower end of the diverter tubes 68, a cleanout means 74 may be provided. A simple cleanout arrangement comprises short pipe sections 75 communicating separately with the base portions of the columns 62 and extending downwardly a sufficient distance below the floor 26 so that a removable drain cap 76 at the lower end of the pipe 75 is readily accessible. Thus the accumulated sediment may be periodically flushed from the columns 62 by opening the drains.

The tubular metal columns 62 and rails 64 are protected from the intense heat of the furnace by a covering of insulation 78. The insulation is usually frangible and incapable of supporting the large steel slabs or workpieces 80. Therefore, workpiece supporting pads 82 or nodules are attached in an aligned or slightly staggered manner along the top of the rails 64 and protrude above the insulation 78 a short distance (see FIGS. 8 and 9). The relative size, shape, and disposition of these pads and the method of attaching them is important because they must support the workpieces 80 during the heating period without marring or unduly chilling a contacting area of the workpiece 80. Preferably each pad 82 is a solid cylindrical section of heat resistant alloy with its base end integrally attached to the top of the rail 64, such as by butt welding, to provide a substantially complete heat conductive relationship therebetween. The weld 84 produces an enlarged heat conductive section at the bases of the pads 82 and improves the heat transfer from the pads 82 to the rails 64. Heat transfer from the top surfaces of the pads 82 into the rails 64 is further enhanced if the heights of the pads 82 from the rails 64 to the top surface of the pads are kept to less than two diameters and preferably to about one diameter or similar proportions. Pads having other cross-sectional forms, such as an elliptical or oval shaped form, may be used provided that the pad dimension in a direction along the rail is small. With such pads 82 the common problem of warping or distortion prevalent with elongated work support pads is eliminated. The solid cylindrical form with its circular cross section has a minimum peripheral edge per unit of cross-sectional area and has no corners, such as are found on angular forms and which are particularly subject to burn-off. Also, the peripheral edge of the flat top surface of each pad may be rounded as at 86. For these reasons, distortion of the top ends of the pads 82, which extend above the insulation and are constantly subject to the heat of the furnace and in intermittent contact with the heated workpiece, is reduced and there is less likelihood of marring the contacting surfaces of the workpiece 80. The spacing of these pads 82 along the rails 64 is related to the distance that the reciprocable conveyor assembly 60 travels in one stroke so that during a subsequent cycle of the conveyor assembly 60 any one of the pads 82 does not contact the same surface area of the workpiece 80 as was in contact with any one of the pads 82 during the immediately preceding cycle. This prevents the repeated chilling of the same spot of the workpiece due to its contact with the pads 82. It also permits exposure to the heat of the furnace of all spots precedingly chilled by contact with pads 82.

' The movable conveyor assembly 60 has approximately the same structure inside of the refractory chamber 22 as the fixed conveyor assembly 58. It has four longitudinal rows of vertical columns 92 mounting parallel horizontal rails 94 with workpiece supporting pads 82 welded thereto to form a horizontal bed extending from one end of the refractory chamber to the other. The columns 92 are also aligned in lateral rows and extend downwardly through elongated slots 96 in the floor 26. The bases of columns 92, which extend beneath the floor 26 and floor framework, are severally welded to base plates 97 and have stiffening bars 98 welded on two of their sides to prevent the columns from tilting laterally with respect to the conveyor 60. The cooling fluid may be pumped into the bottom of end columns 92 and then into the adjoining ends of the rails 94 adjacent the end wall 34. The other ends of the rails 94 extend through the entry end opening 36 of the refractory chamber 22 and connect with the end columns 92" which are located outside the chamber 22. The cooling fluid may exit through branch lines 99 connected to the outside vertical column 92 located adjacent the entry end wall 32. Diverter tubes 68 and sediment clean-out means 74 for the vertical columns 92 are the same as provided for columns 62.

The upright columns 92 are removably mounted upon a horizontally disposed rectangular framework or carriage 100 comprising a pair of longitudinally extending beams or girders 102 positioned below a gridlike carriage bed 104 formed of laterally 106 and longitudinally 108 extending beam members welded together. The webs of the girders 102 are of substantial height and therefore subject to tilting so struts 110 are provided which extend angularly upward from the base flanges of the girders 102 to the carriage bed 104. A series of laterally extending cross beams 112 of lesser dimensions than the girders 102 are attached to central web portions of the girders 102 to further rigidify the carriage 100. Vertical pedestals 114, which may be made from a short section of I beam, are welded to the sides of the longitudinal beams 108 or stringers directly under each column 92, 92, and 92". The lateral beams 106 are in the form of channel irons and are arranged in pairs with their webs abutting the pedestals 114 and welded to them. Plates 116 corresponding in size to the column base plates 97 are welded to the top of pedestals 114. The mating pairs of plates 97 and 116 have vertically aligned apertures for removably connecting them together by fasteners such as bolts 118 and nuts 120-.

The slots 96 in the floor of the refractory chamber 22 are hermetically sealed to prevent cold air or hot furnace gases from entering or exiting the chamber 22 and to enable better control of the operating pressures within the furnace. The seal means comprises imperforate skirts 122 depending from adjacent the peripheries of each slot 96 into a liquid, such as water, contained in seal troughs 124 mounted upon the carriage bed 104 directly beneath the longitudinal rows of slots 96 (see FIG. 7). The troughs 124 may have inverted V-shaped bottoms 126 and upright sides 128 and 130 so that any scale or sedimentary particles which fall into the troughs or collect therein will gravitate towards the sides 128 and 130. Upright open ended box sections 132, with walls extending above the liquid level in the troughs 124, are provided in the central portions of the troughs around each pedestal 114. The open upper end of each box section 132 is covered by a shroud 134 which may be attached between each column base plate 97 and its mating plate 116 and depend into the liquid in the troughs 124 around each box section 132. Preferably there is a clearance space between each shroud 134 and box section 132 to allow for limited movement between these members without causing distortions of them and possible impairment of the seal. The box sections 132 are spaced inwardly from both side walls 128 and 130 of the troughs so that scale and the like particles may be urged along the troughs past the box sections by pushers or paddles 136 mounted on the lower edges of the longitudinal sides of the skirts 122. Additional paddles 138 conforming in shape with the interior of the troughs 124 are located at intervals along the troughs between the box sections 132 and aflixed to the refractory floor framework. Since the seal troughs 124 and carriage are reciprocated or orbited together around a substantially rectangular path in a vertical plane with respect to the stationary paddles 136 and 138, the sedimentary particles which collect in the seal troughs are urged along the troughs m a direction from the extractor end 34 to the entry end 32 of the furnace 20.

A scale accumulator 140 is provided at the downstream end of each trough 124. Periodically the accumulated scale may be flushed from each accumulator by actuating a pneumatic cylinder 142, or the like, for lifting a plunger 144 that has a plug end 146 which seats in the conical bottom opening of the accumulator 140. The plunger 144 may be a vertically hollow tube extending upwardly with a flaired opening 148 at its top end to function as an overflow pipe for maintaining the water level in the trough when the plunger is in a closed position. Only a llmlted amount of water is allowed to flow out of the trough during the flushing operation because a secondary closure member 150, located intermediate the ends of the plunger 144, cooperates with a conical sectron lnside the accumulator and serves to shut off the flow of water while the plunger is at the top of its stroke. The scale and water fall from each accumulator into a short section of discharge trough 152 and the scale is moved to one end of this trough 152 and disposed of. To reduce the amount of scale entering the troughs 124 through the slots 96, small peripheral dikes or barrier ridges 154 are provided at the top edge of each slot 96.

As was mentioned previously, the carriage 100 is reciprocated or orbited in a substantially rectangular path with respect to a vertical plane. This is accomplished by means of a vertical travel drive assembly 156 and a horizontal travel drive assembly 158 (see FIGS. 1, 3, 4, and 5). The vertical drive assembly 156 comprises two rows of roller-ringed eccentrics 160 located laterally opposite each other at intervals along the underside of the girders 102. These eccentrics 160 raise and lower the carriage 100 and are driven in unison by a single large electric motor 162 operating through a series of right angle drives 164 and reduction gears 166 and 168. The right angle drives 164 are located beneath the longitudinal centerline of the furnace 20 and have a main drive shaft means 170 connecting them together and to the motor 162. Extending laterally from these drives 164 are secondary drive shafts 172 with pinion gears 166 attached to their outboard ends. The pinion gears 166 drive large ring gears 168 connected to the shafts of the eccentrics 160 which shafts are journaled on concrete pillars 174.

Each eccentric 160 has an outer peripheral surface which mounts inner race sections 176 and 178 for a double row of inwardly inclined tapered roller bearings 180 and 182 with the small ends of the bearings in both rows adjacent each other (see FIG. 6). The inner race sections 176 and 1 78 have a seal 184 between them and are positioned by annular rings 186 and 188 bolted to the sides of the eccentrics 160. The outer race member 190 has a relatively thick roller ring 192 surrounding it and which is free to rotate with respect to its eccentric member 160. Annular seals 194 and 196 and seal retaining rings 198 and 200 bridge the gaps between the inner 186 and 188, and outer 198 and 200 seal rings. The carriage 100 is rested or supported upon the roller-ringed eccentrics 160 without any positive connecting linkage therebetween. Rather than resting or supporting the girders 102 directly on the roller rings 192 of the eccentrics 160, spacers or risers 202 comprising short sections of I beam are removably attached to the griders above each supporting roller-ringed eccentric. By jacking up the carriage 100 and then removing the risers 202, the carriage may then be lowered substantially so as to facilitate maintenance of the parts and assemblies mounted on the carriage 100.

The horizontal drive 158 which reciprocates the carriage 100 in horizontal directions is located beneath the girders 102 adjacent the extractor end 34 of the furnace 20. It compries a pair of crankshafts 204 journaled on concrete pillars 206 and operated in unison by a drive train including a large ring gear 208 attached to the crankshafts 204. The ring gears 208 are rotated by pinion gears 210 connected to the outboard ends of a pair of secondary drive shafts 212 extending laterally from a right angle drive 214 which has a drive motor 216 connected thereto by a primary drive shaft 218. A pair of connecting rod 220 journaled on the throws of the crankshafts 204 are pivotally attached to the undersides of a corresponding adjacent pair of risers 202 which are elongated to provide space for attaching the connecting rods 220 without interfering with the operation of their associated roller rings 192 (see FIG. 1). The horizontal drive assembly 150 provides the only positive longitudinal linkage between the movable carriage 100 and a stationary member, such as pillars 206.

When the carriage 100 is at either end of its horizontal stroke and also in the mean position of its vertical stroke, the connecting rods 220 are horizontally disposed. Thus the positive linkage between the reciprocable carriage 100 and the stationary pillars 206 does not cause a net horizontal displacement during a complete vertical stroke. The radius of the slightly arcuate vertical path of the carriage depends upon the length of the connecting rods 220 and involves only slight and equal movement in both horizontal directions.

The vertical and horizontal drives 156 and 158 may be operated alternately and independently of each other and braking means may be provided for both of these drives to alternately stop the movement of one of them at the end of its stroke. This produces a substantially rectangular path of movement in a vertical plane with the horizontal sides of the path being straight lines and the vertical sides of the path being slightly arcuate, Since the vertical drive 156 and horizontal drive 158 are independent of each other, portions of their cycles may be overlapped to any desired extent. The use of the braking means may be reduced or eliminated if the drive motors 162 and 216 are timed to shut off prior to reaching the end of their respective strokes so that the momentum of the drive components and the carriage causes the carriage to glide slowly through an extreme portion of one stroke while the alternate drive means is performing the major portion of its stroke. This produces a substantially rectangular path as shown in FIG. 7, in which all of the sides are slightly arcuate. Orbital paths of other desired shapes may be produced by the apparatus described above. Also, means to vary the speeds of the drive motors and reverse their directions may be provided to further increase the conveyors versatility.

Guideways such as the guideway shown in FIG. 3 may be provided beneath each end of the carriage 100 to prevent the carriage from drifting laterally during operation. Each guideway may comprise a pair of spaced bearing plates 222 and 224 vertically depending from the carriage bed 104 and embracing the vertically disposed fianges of a beam section 226 supported by means of strut member 228 and 230. The beam section is aligned with the centerline of the furnace and horizontally disposed.

The workpieces are seriately pushed by an entry ram means 232 onto an entry table 234 where they are picked up by the movable conveyor assembly 60 and walked laterally through the chamber 22 in spaced relationship until they reach the extractor end 34 of the chamber. Extractor arms 236 reach into the chamber 22 and seriately lift the workpieces 80 from the stationary conveyor assembly 58 and then deposit them on the extractor table 238 where they are moved to a subsequent operation, such as a rolling, forming, quenching, or the like operatlOIl.

While there is described above the observed principles of this invention in connection with specific apparatus, it is to be clearly understood that there may be many unobserved side effects which contribute substantially to the efficiency of this device and that this description is made only by way of example, and not as a limitation to the scope of this invention.

I claim:

1. In a walking beam type conveyor for conveying workpieces through the refractory chamber of a furnace, the combination comprising: at least two sets of conveyor rails for alternately supporting said workpieces, with at least one set of said rails being mounted upon a carriage for moving said one set of rails in unison relative to one other of said sets of rails, said carriage having a pair of parallel girders extending along the underside of said carriage for supporting said carriage on at least four rotatable eccentrics for vertically reciprocating said carriage, and means for horizontally reciprocating said carriage independently of the vertical reciprocation thereof.

2. A conveyor according to claim 1 wherein said rotatable eccentrics are synchronously driven circular eccentrics each having a freely rotatable peripheral ring bearing against an underside section of said carriage.

3. A conveyor according to claim 1 wherein the path of movement of said carriage substantially describes a rectangle in a vertical plane.

4. A conveyor according to claim 1 wherein the set of rails mounted upon said carriage are horizontal disposed rails supported by vertical columns which extend through liquid sealed slots in the fioor of said refractory chamber.

5. A conveyor according to claim 1 wherein said rails further comprise exteriorly insulated liquid cooled pipes having upright workpiece supporting pads which protrude above the insulation and which are made from heat resistant material in the general form of a short solid bar section and are butt welded along the top of said pipes in a spaced apart relationship.

6. A conveyor according to claim 5 wherein said pads are spaced in relation to the horizontal distance said workpiece travels in one cycle so that the pads supporting the workpieces during an immediately subsequent cycle do not contact exactly the same surface areas contacted by the pads during the preceding cycle.

7. A tunnel furnace with a reciprocable conveyor for conveying workpieces through said furnace the combination comprising:

(a) an elongated refractory chamber having a floor, a ceiling and side walls, and with an entry opening at one end and an exit opening at the other end, said floor having rows of slots extending through its floor with sealing flanges depending from adjacent the peripheries of said slots;

(b) said movable carriage having at least twovsets of conveyor rails for alternately supporting said workpieces, with at least one set of said rails being mounted upon a carriage for moving said one set of rails in unison relative to one other of said sets,

(1) a reciprocable base frame located beneath said floor,

(2) a plurality of rows of vertical columns rigidly attached to said base frame and extending upwardly through said slots, and

(3) workpiece supporting rails mounted on said rows of vertical columns;

(c) liquid filled elongated troughs surrounding each of said vertical columns and deployed on said carriage directly beneath said slots so that said seal flanges remain immersed in said liquid during reciprocation of said carriage; and

(d) means for reciprocating said carriage vertically and horizontally.

8. An apparatus according to claim 7 wherein a plurality of stationary pushers depend into said troughs whereby the movement of said troughs with respect to said pushers urges scale and other sedimentary particles towards one end of said troughs.

9. An apparatus according to claim 8 wherein said troughs have vertical walls and inverted V-shaped bottoms causing scale and sediment to gravitate away from the center of said troughs towards the walls thereof to facilitate passage of the scale and sediment around said vertical columns in said troughs.

10. An apparatus according to claim 8 wherein said one end of each trough has an accumulator for the scale and sediment, which accumulator has means for periodically discharging accumulated'scale and sediment.

11. A water cooled conveyor for a tunnel furnace, the combination comprising:

(a) a tubular rail generally horizontally disposed within the heating chamber of said furnace said rail having liquid coolant flowing from one end towards the other end,

(b) tubular support columns in fluid communication with said rail, and

(c) an internal diverter pipe of substantially smaller diameter supported inside each of said tubular columns and having an inlet elbow section confronting the fluid flow through said rail and an outlet opening adjacent the base of said tubular column.

12. A conveyor according to claim 11 wherein said tubular support columns have a drain means communicating with their base ends.

13. A conveyor according to claim 11 wherein said rail is externally insulated and has workpiece supporting pads attached along the top of said rail with their bases in substantial heat conductive relationship with said rail and the substantially flat tops of said pads extend above said insulation.

14. A workpiece supporting pad for attachment with a plurality of like pads spaced along the top of an internally cooled conveyor rail disposed within the heating chamber of a furnace, said pad comprising: a base section attached to said rail in a substantial heat conductive relationship therewith, and a reduced top section having a workpiece contact surface which is generally elliptical in form and is disposed coplanar with adjoining pads and wihich is substantially flat but has rounded peripheral e ges.

15. A workpiece supporting pad according to claim 14 wherein the conveyor rail is externally insulated, the insulation surrounds an enlarged base section of the pad, and the top section of the pad protrudes above the insulation.

16. A workpiece supporting pad according to claim 14 wherein the height of said pad from said rail to said workpiece contact surface of said pad is less than twice the largest dimension of said surface.

References Cited UNITED STATES PATENTS 805,041 11/ 1905 Turner. 3,398,939 8/1968 Morton.

FOREIGN PATENTS 303,830 1/ 1929 Great Britain.

JOHN J. CAMBY, Primary Examiner US. Cl. X.R. 198219 Disclaimer 3,471,134.-0ar?-0ll Gone, Maumee, Ohio. WALKING BEAM FURNACE.

Patent dated Oct. 7, 1969. Disclaimer filed Oct. 16, 1970, by the assignee, MidldIZd-ROSS Gama ration. Hereby enters this disclaimer to claims 13 through 16 of said patent.

[Oflicz'al Gazette March 2, 1.971.] 

